A communication network operates to communicate data between two, or more, communication stations. A communication network is formed, at a minimum, of a first communication station, forming a sending station, and a second communication station, forming a receiving station. The communication stations are interconnected by way of a communication channel. And data that is to be communicated by the first communication station to the second communication station is sent to the second communication station by way of the communication channel. The data that is to be communicated is converted by the first communication station into a form to permit its communication upon the communication channel. And the second communication station operates to detect the data communicated thereto and to recover the informational content thereof.
Many different types of communication networks have been developed and implemented to effectuate the communication of the data between the communication stations. And with continued advancements in communication technologies, new types of communication networks, as well as improvements to existing communication networks, have been, and continue to be, made.
A radio communication network is an exemplary type of communication network. A radio communication network utilizes radio communication channels upon which to transmit the data that is to be communicated between the communication stations operable therein. Radio communication channels are defined upon radio links forming part of the electromagnetic spectrum. As a radio link is utilized upon which to define the communication channels, the need otherwise to utilize wireline connections upon which to define communication channels is obviated. Implementation of a radio communication network is generally less costly than the corresponding costs that would be required to construct a conventional, wireline communication network. And a radio communication network can be implemented to form a mobile communication network.
A cellular communication network, exemplary of a radio communication network, has been widely implemented and has achieved wide levels of usage. A cellular communication network provides for radio communications with mobile terminals. The mobile terminals permit telephonic communication to be effectuated therethrough. A cellular communication network includes a network part that is installed throughout a geographical area and with which the mobile terminals communicate by way of radio channels. Base transceiver stations, forming portions of the network part of the communication network, are installed at spaced apart locations throughout the geographical area that is to be covered by the communication network. Each of the base transceiver stations defines a cell encompassing a portion of the geographical area. When a mobile terminal is within the cell defined by a base transceiver station, communications are generally effectuable with the base transceiver station that defines the cell.
As a mobile terminal travels between cells defined by different ones of the base transceiver stations, communication handoffs are effectuated to permit continued communications by, and with, the mobile terminal. Through appropriate positioning of the base transceiver stations, only relatively low-powered signals need to be generated to effectuate communications between a mobile terminal and a base transceiver station. Hand-offs of communications between successive base transceiver stations, as the mobile terminal moves between cells permit the continued communications without necessitating increases in the power levels at which the communication signals are transmitted. And, because only relatively low-powered signals need to be generated to effectuate communications, the same radio channels can be reused at different locations of the same cellular communication network. Efficient utilization of the frequency-spectrum allocation to the cellular communication network is thereby possible.
Various operating specifications have been promulgated that define operational parameters by which cellular, as well as other, communication networks are to be operable. Successive generations of cellular communication networks, incorporating technological advancements, as such advancements become available, have been defined by successive generations, or updates to, operational specifications. First-generation (1G) and second-generation (2G) networks have been widely implemented and have achieved significant levels of usage. In this regard, the goal of second generation (2G) networks (e.g., IS-95) was to enable pre-defined mobile telephony services that were spectrum efficient and economically viable. The result was a network that provided mobile low rate circuit switched voice communications and low rate data communications. The success of 2G is evidenced by its consumer acceptance and popularity that exceeded expectations. As more consumers used mobile terminal services, certain increasing numbers of them manifested a desire for more capacity in both voice and data. The cellular industry responded with third-generation (3G) (e.g., cdma2000) networks, the next generation that introduced packet switched data networks.
Code Division Multiple Access (CDMA) was introduced into cellular based, mobile communication systems in the early 1990s with the introduction of the IS-95 standard. Since then, CDMA technology has been well accepted in the wireless industry and has been widely disseminated reaching literally hundreds of millions of subscribers throughout the world. More recently, 3G backward-compatible evolutions of the IS-95 standard, such as the cdma2000 1X standard, have been developed to further improve the voice service capacity of CDMA while providing higher data rates for data services. As part of this evolution, the cdma2000 1X-EVDO network was developed to optimize wireless, high speed packet data services, such as may be facilitated by the Internet Protocol (IP). However, as networks such as cdma2000 1X-EVDO only support packet data services, mobile terminals, sometimes referred to as hybrid terminals, have been developed that are capable of accessing networks, such as cdma2000 1X, that provide both voice and data services, as well as networks such as cdma2000 1X-EVDO that provide higher-speed packet data services. Thus, a hybrid terminal could utilize a cdma2000-1X network for voice communications and for short message service (SMS), and a cdma2000-1X-EVDO network for multimedia message service (MMS) and for other data communications.
In a network such as cdma2000 1X or 1X-EVDO, when a message (i.e., a “call”) is to be terminated at a mobile terminal, the network infrastructure broadcasts a paging message to alert the mobile terminal of the message. Monitoring channels of the respective network, the mobile terminal detects the paging message and, in response, performs various operations to receive the terminating message. With respect to the detection of a paging message, slotted mode operation was introduced in cdma2000 1X systems to conserve the life of a mobile terminal's battery. In this regard, the channel via which paging messages are transmitted, e.g., the forward common signaling logical channel (f-csch), is divided into 2048 slots. A mobile terminal operating in slotted mode is therefore assigned one of the slots and only needs to monitor its assigned slot and subsequent slot. See, for example, FIG. 1. Other than its assigned slot and the subsequent slot, the mobile terminal can opt to turn off its receiver/transmitter and to defer other non-vital processing. Each paging slot in a cdma2000 1X system is 80 ms in length and the slot assigned to a mobile terminal is determined through a hash algorithm defined in the cdma2000 1X standard. By way of example, the hash algorithm takes the phone number (MIN) of the mobile terminal and determines which slot of the 2048 possible slots (denoted slots 0˜2047) is the slot assigned to the mobile terminal. Since the cdma200 1X network also uses the same hash algorithm, the network is also aware which is the slot assigned to the mobile terminal.
Also defined in a cdma2000 1X system is the concept of a slot cycle. In this regard, once a mobile terminal determines its assigned slot, the mobile terminal will wake up every slot cycle to check if there is page indication or other message addressed to it in its assigned slot or in the subsequent slot. As shown in FIG. 1, the mobile terminals may have different slot cycles with the cycle of MN 0 being 1.28 seconds and the cycle of MN 7 being 2.56 seconds, for example. Moreover, by permitting messages to be transmitted to the mobile terminal both in its assigned slot and in the subsequent slot, the network has improved flexibility in regards to the scheduling of the messages to the mobile terminal which is particularly useful in instances in which the paging channel is crowded.
Since there are only 2048 possible slot positions, different mobile terminals can be assigned the same slot. See FIG. 1 in which MN 0, MN 3 and MN 4 are all assigned to one slot, and MN 1 and MN 7 are all assigned to another slot. Before monitoring its assigned slot, a mobile terminal does not know whether there will be pages/messages for the mobile terminal in its next assigned slot. If the network does not need to page or transmit any other message to any of the mobile terminals in that assigned slot, the network advantageously advises the mobile terminals assigned to the slot as soon as possible within the slot so that mobile terminals can go to sleep as early as possible, thereby further conserving battery power. As shown in FIG. 2, the mechanism in a cdma2000 1X network is to set the CLASS—0_DONE field to ‘1’ in the General Page Message (GPM) to indicate that there are no pages/messages for the mobile terminals of the respective slot. Upon receiving this GPM in the assigned slot, the mobile terminals can go to sleep immediately, i.e., prior to the end of the slot as shown in FIG. 2. In the common instance in which many mobile terminals utilize the same slot, the network cannot transmit the GPM with the CLASS—0_DONE field set to 1 until any messages have been transmitted to the mobile terminals assigned to the slot. For those mobile terminals that are not receiving a message, the mobile terminals must stay awake, during the transmission of messages to other mobile terminals, thereby unnecessarily consuming battery power.
As will be appreciated by those skilled in the art, however, in various instances of operating in a network such as cdma2000 1X, a mobile terminal may not otherwise monitor for paging messages from a cdma2000 1X-EVDO network, thereby conserving battery power. For example, a mobile terminal may initially be operating in a cdma2000 1X-EVDO network in conjunction with a data application, e.g., the download of an ftp file. At some point in time, the data application may go dormant, such as upon completion of the ftp file download, and the mobile terminal may be placed in an idle state by the cdma2000 1X-EVDO network. The mobile terminal may thereafter switch to a cdma2000 1X network. The mobile terminal may switch to the cdma2000 1X network for many reasons including the loss of network services by the cdma2000 1X-EVDO network coupled with the discovery of network services by the cdma2000 1X network or the placing of a voice call by the mobile terminal. Since the mobile terminal is now monitoring a different frequency for signals from the cdma2000 1X network than from the cdma2000 1X-EVDO network, the mobile terminal will no longer be monitoring for paging messages from the cdma2000 1X-EVDO network. In addition to frequency differences, differences in the over-the-air technology between two networks would also prevent the mobile terminal active in one network from monitoring for paging messages in another network. In such instances, although the cdma2000 1X-EVDO network may have a message to be terminated at the mobile terminal operating in the cdma2000 1X network, such as an advertisement or the download of a new movie, the cdma2000 1X-EVDO network may be unable to reach the mobile terminal via a paging message.